Reciprocatory electromagnetic motor



April 26, 1949. 1.. .CLPARKER 2,468,343

r 7 RECIPROCATORY ELECTROMAGNETIC MOTOR Filed Aug. 26, 1947 V 2sheets-sheet 1 IN VEN TOR.

HWIYTNESI'S: v I 5% 2. M XE j I L. C. PARKER v RECIPROCATORYELECTROMAGNETIC MOTOR 2 Sheets-Sheet 2 Filed Aug. 26, 1947 INVENTOYR.

fzr/zer' mzwz'm:

Patented Apr. 26, 1949 Leland 0. Parker, Elmira, a. r assi nor t6 BendixAviation Corporation, a corporation of Dela- WIN Application August 26,1947, Serial No. 170,611 '3 Claims. (01. 172-126) The present inventionrelates to a reciprocatory electromagnetic motor, and more particularlyto the means for controlling the 'energization of the actuatingelectromagnet of such motor.

In reciprocating motors such as used to actuate fuel pumps and the like,the actuating electromagnet is customarily controlled by contacts whichare operated magnetically by the approach and recession of the pumppiston. The contactcontrolllng magnet is usually a permanent magnetwhich may be mounted on the contact-carrying member or may be mounted onthe piston, in which latter case the contacts are controlled by amovable armature. In both cases, the flux of the magnet must traverse anair gap of considerable width in order to magnetize the armature or thepump piston as the case may be, to cause closure of the contacts. Thismakes it necessary to use a larger permanent magnet than would otherwisebe needed, and tends to make somewhat indefinite the points in thetravel of the piston where the contacts open and close.

It is an object of the present invention to pro-.

vide a novel reciprocatory electromagnetic motor which is simple andeconomical in construction while being efilcient and reliable inoperation.

It is another object to provide such a device incorporating contacts forcontrollin the motivating electromagnet, and novel actuating means forsaid contacts. i

It is another object to provide such a device in which the actuatingmeans for the contacts includes a pair of permanent magnets arranged tomagnetize the piston when it comes between them.

It is another object to provide'such a device in which one permanentmagnet is movable audactuates the control contacts, while the other isfixed and located closely adjacent the path of the piston at the pointwhere the contacts are to be closed.

Further objects and advantages will be apparent from the followingdescription taken in connection withthe accompanying drawings, in which:

Fig. l is a vertical substantially mid-sectional view of a preferredembodiment of the invention as used in a fluid pump, the upper part ofthe device being sectioned substantially on the line il of Fig. 2, andthe electrical system therefor being indicated diagrammatically;

Fig. 2 is a section taken substantially on the line 2--2 of Fig. 1;

Fig. 3 is a detail of a modified form of the device shown in verticalsection, the section being taken substantially on the line I -i of Fig.2; and Fig. 4 is a side elevation of a pump unit on a reduced scale.

In Fig. 1 of the drawing, there is illustrated a cylinder I ofnon-magnetic material in which is slidably mounted a piston 2 ofmagnetic material such as soft iron. A pole piece 3 of magneticmaterialis fixedly mounted in the lower end of the cylinder in anysuitable manner, and a spring 4 located between the pole piece andpiston urges the piston toward a cylindrical stop member 5 of cushioningmaterial such as rubber or fibre in the upper end of the cylinder.

An electromagnet 6 surrounding the cylinder is arranged when energizedto. attract the piston toward the pole piece 3 against'the action ofspring 4, the magnetic 'circuit being preferably completed through thelower and upper plate members I and 8 and the case 9, all of which aremade of magnetic materiaL.

An electrical system for energizing the electromagnet 6 is providedcomprising a battery It grounded at I! and connected by a manual switchl3 and lead It to one terminal of the electromagnet 6. The otherterminal of the electromasnet is connected by a lead IE to a fixedcontact l6 (Fig. 2). which is mounted on a bracket'l'l, the contact Ibeing suitably insulated from the bracket as indicated at l8. A movablecontact i9 is mounted on a flexible blade member it which is fixed tothe upper plate member 8 by means of a bracket 22 and is grounded asindicated at 23 so.as to complete the energizing circuit for theelectromagnet 6 when the contacts l6 and 19 are in engagement.

Means for controlling the contacts [6- and I9" is provided comprising apermanent magnet 24 mounted on the elastic blade it in position to movetoward and away from the cylinder I. The

blade 2| is arranged to urge the magnet 24 away der. The magnet 26 isthus'efl'ective to strongly magnetize the upper end of the piston. Thepoles of the first mentioned permanent magnet 24 are oriented similarlyto those of the second magnet on 26, so that the adjacent poles of themagnet 24 and of the piston as magnetized by the magnet 26 are ofopposite polarity. The magnet 24 is therefore strongly attracted by thepiston, causing the magnet to flex the blade 2| and bring piece 3. Whenthe upper end of the piston leaves the zone of influence of thepermanent magnets 24, 26, the permanent magnet 24 is released and theblade 21 moves said magnet back against the stop and deenergizes theelectromagnet 6. The spring 4 is thereupon operative to move the pistontoward the upper end of the cylinder, such motion bein utilized in thestructure illustrated to propel fluid from the cylinder I. When theupper end of the piston comes opposite the permanent magnet 26, thepiston becomes magnetized thereby and attracts the permanent magnet 24so as to close the control contacts [6, 19 whereby the cycle isrepeated.

The magnet 26 may be located directly opposite the magnet 24 or, asillustrated in Fig. 3, it

may be spaced axially of the cylinder in respect to magnet 24. Since,when the contacts are open, there is a substantial air gap between thepermanent magnet 24 and the cylinder I, the magnet 24 will not becomeeffective to close the contacts until the piston has been magnetized bymagnet 26. The position of magnet 26 thus determines the point in thetravel of the piston at which the contacts will be closed. Since the airgap between the magnet 24 and the cylinder is substantially closed whenthe contacts are closed, the piston will hold the contacts closed aslong as it is in proximity to the magnet 24. It will thus be seen thatconsiderable latitude of adjustment of the length of the stroke ofpiston 2 4 may be secured by adjustment of the magnet 26 axially of thecylinder I;

Although certain structure has been shown and described in detail, itwill be understood that other 4 the parts without departing from thespirit of the invention.

I claim:

1. In a reciprocatory electromagnetic motor, a cylinder of non-magneticmaterial, a piston of magnetic material slidably mounted therein, aspring for actuating the piston, an electromagnet surrounding thecylinder operable when energized to overcome the spring and retract thepiston, means for controlling the energization of the electromagnetincluding a pair of contacts and means for actuating the contactsincluding a permanent magnet mounted adjacent the cylinder and movabletoward the'cylinder by attraction of the piston therein to close thecontacts, means for magnetizing'the piston to cause it to attract saidmagnet including a second permanent magnet mounted closely adjacent thepath of the piston at the end of its forward stroke and arranged toinduce in the piston a polarity opposite to that of the first permanentmagnet and yielding means normally holding the first mentioned permanentmagnet so separated fromthe cylinder as to be ineffective to close thecontacts except when the piston is magnetized by proximity to'the secondpermanent magnet.

2. An electromagnetic motor as set forth in claim 1 in which the secondpermanent magnet is arranged substantially on the opposite side of thecylinder from the first-mentioned permanent magnet and in contact withsaid cylinder.

3. An electromagnetic motor as set forth in claim 1 including further,yielding means urging the first-mentioned permanent magnet away from thecylinder to hold the contacts open, and means limiting the movement ofthe first-mentioned permanent magnet away fromthe cylinder .to definethe air gap between said magnet and embodiments are possible and variouschanges {54) may be made in the design and arrangement of the cylinder.

LELAND C. PARKER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 355,815 Ghegan Jan. 11, 18871,640,741 Wallace Aug. 30, 1927 2,086,754 Werner July 13, 1937 2,249,321McDermott July 15, 1941

